The New York Times

June 23, 2002

Lessons From Networks, Online and Other

By WILLIAM J.
HOLSTEIN

ALBERT-LASZLO BARABASI, a professor of physics at the University of Notre Dame, became
fascinated with the structure of the Internet in 1998. He and his student
researchers designed software robots that went out on the Net and mapped
as many of its nodes, hubs and links as they could. He then began studying
other networks and found that they had similar structures. The Internet in
particular, he found, had taken on characteristics of a living
ecosystem.

That made for a valuable insight in itself. But Professor Barabasi went
a step further and analyzed the genetic networks of various living
organisms, finding that their genes and proteins interacted in much the
same networked way as the Internet.

This conclusion, described in Professor Barabasi's new book, "Linked:
The New Science of Networks" (Perseus Publishing, $26), could alter the
way we think about all the networks that affect our lives. Those networks
may be Hollywood power brokers, Vernon E. Jordan Jr.'s corporate board
directorships or Al Qaeda terrorists. The Apostle Paul had a network of
cities to spread Christianity.

Professor Barabasi's well written book will be understandable to most
readers, but its core concept takes a moment to absorb.

Start by thinking of a highway map of the United States before the
advent of the Interstate System. Each city, or node, was connected pretty
much at random to others in the network of American cities. Each city has
the same relative weight, or "scale," in Professor Barabasi's terminology.
Knocking out one city doesn't disrupt the network. Traffic can be rerouted
easily.

In contrast, consider the airport hub-and-spoke system that dominates
the nation's airline transportation. A few nodes like Chicago, Atlanta and
Dallas-Fort Worth have become far more important than, say, Lincoln, Neb.
Knocking out the important nodes has serious cascading effects throughout
the network.

This is similar to a disruption on the Internet. Because the nodes of
these networks do not have the same scale, Professor Barabasi calls them
scale-free, a concept that permeates the book.

Once you understand that concept, you're off on an intellectual
detective journey. Professor Barabasi has invented a vocabulary to talk
about the structure of networks.

"We are witnessing a revolution in the making as scientists from all
different disciplines discover that complexity has a strict architecture,"
he writes. These networks do not operate at random, the author contends;
there are laws that govern their behavior.

In the case of human genes, scientists have decoded the genes and
proteins of DNA, but that is just the first important step in
understanding how genes and proteins interact, Professor Barabasi says.
The next step, he writes, is understanding how genes and proteins interact
as part of a network, and he predicts the discovery of a clear set of
rules for their behavior that will help unlock some mysteries of the human
body.

Professor Barabasi makes that prediction partly because he and his
researchers mapped out the interactions of 43 primitive organisms and
found they took the form of a network with rules.

There are many examples of scale-free networks. Even a cocktail party
can be mapped that way: the most sociable people are the "hubs" that link
all the guests in a pattern that can be drawn. Other scale-free networks
include the electrical power grid, companies and consumers linked by trade
and the nervous system of living creatures.

Business writers have long talked about "network effects," meaning
that a network generates more power than individual parts can do by
themselves. That was part of the intellectual case against allowing Microsoft
to dominate so many personal computers using its operating system.

But Professor Barabasi has put more flesh on the relatively primitive
concept of the network effect. His work is relevant not only to physicists
and mathematicians, but also to business executives, computer scientists,
sociologists and biologists.

Networks have strengths and weaknesses, and Professor Barabasi contends
that we have to understand both. On the positive side, because of the
multiplicity of connections, some things happen quickly. A good idea can
win rapid acceptance.

Professor Barabasi uses the example of Hotmail's explosion in
popularity. Created on July 4, 1996, by Sabeer Bhatia and Jack Smith, it
had one million users within a year. By the time Microsoft came knocking
on the door to buy it a year later, it had 10 million. "Innovations and
products with a higher spreading rate have a higher chance of reaching a
large fraction of the network," he argues.

By contrast, networks have what he describes as an Achilles' heel.
Knocking out a single major hub can cripple the network, which the Sept.
11 attacks almost succeeded in doing. In the United States, the airline
system, financial markets and telecommunications networks all suffered
grievous blows.

The extensions of Professor Barabasi's thinking go in many directions.
What caused Cisco
Systems and other technology companies that outsource much of their
production to be so clobbered in 2000 and 2001? Cisco, in particular, had
bragged that its Internet-based supply chain meant that it would never be
surprised by having too much inventory. But, Professor Barabasi writes,
Cisco did not understand network effects and had to pay for billions of
dollars' worth of components in its extended supply chain; oddly, Cisco,
the master of the network, didn't think in network terms.

"A me attitude, where the company's immediate financial balance is the
only factor, limits network thinking," Professor Barabasi says. "Not
understanding how the actions of one node affect other nodes easily
cripples whole segments of the network."

Professor Barabasi makes a provocative argument about "the market." For
hundreds of years, economists like Adam Smith have argued that there may
be an "invisible hand" guiding the market but at the end of the day people
cannot understand how the market works because it is too big, too complex,
too random.

Nonsense, Professor Barabasi says. "In reality, the market is nothing
but a directed network," he writes. "Companies, firms, corporations,
financial institutions, governments, and all potential economic players
are the nodes."

If you understand the structure and evolution of this network, you can,
in fact, understand how the market performs, the author contends. That is
sure to bring howls of derision from proponents of the dismal science
known as economics.

If there is any criticism that can be leveled at him, it is that the
reader is left wanting to understand more of the implications of his work.
If we understand the network of the human body, can we cure cancer? If we
understand the network of the global economy, can we stop recessions? If
we understand the network of Al Qaeda, can we eradicate terrorism? The
answers may be elusive, but Professor Barabasi's argument suggests that
answers may indeed be found.